Adjustable coverage rotating sprinkler head

ABSTRACT

A positively driven, rotating sprinkler head having adjustable, cam controlled valving means to regulate water flow therethrough to maintain water distribution within predetermined areas not necessarily circularly symmetric. The valving cam may be manually set during operation to visually determine the periphery of the sprinkled area. A second positively driven cam is associated with the output nozzle to particularly deflect the flow of water therethrough to distribute it uniformly within the area watered.

United States Patent Lindgren [54] ADJUSTABLE COVERAGE ROTATING SPRINKLER HEAD [72] Inventor: Robert W. Lindgren, P.O Box 738, Soap Lake, Wash. 98851 [22] Filed: Mar. 6, 1970 21 Appl. No.: 17,113

[52] US. Cl. ..239/97, 239/236, 239/D1G. l [51] Int. Cl ..B05b 3/00 [58] Field 01 Search ..239/97, 236, DIG. l, 240

[56] References Cited UNITED STATES PATENTS 2,805,098 9/1957 Hurley ..239/236 3,095,148 6/1963 Smith ..239/97 5] Mar. 14, 1972 DAgaro ..239/97 Karbo ..239/236 X Primary Examiner-Lloyd L. King Attorney-Keith S. Bergman [57] ABSTRACT A positively driven, rotating sprinkler head having adjustable, cam controlled valving means to regulate water flow therethrough to maintain water distribution within predetermined areas not necessarily circularly symmetric. The valving cam may be manually set during operation to visually determine the periphery of the sprinkled area. A second positively driven cam is associated with the output nozzle to particularly deflect the flow of water therethrough to distribute it uniformly within the area watered.

6 Claims, 7 Drawing Figures PATENTEBMAR 14 I972 SHEET 1 UF 2 FIGZ/flls' 5 FIGZ/QE 4 FIGZ/fiE 1 FIGURE 6 12 obe rt w Bin d ren INVENTOR- I ATTORNEY ADJUSTABLE COVERAGE ROTATING SPRINKLER IIEAD BACKGROUND OF INVENTION 1. Field of Invention This invention relates generally to adjustable rotatable sprinklers adapted to water an irregular area and more particularly to a positively driven, cam regulated sprinkler that provides uniform water distribution over the watered area.

2. Description of Prior Art Mechanically simple rotary sprinklers normally distribute water non-uniformly over a circular area concentric about the sprinkler. It is desirable with such sprinklers that they should distribute water uniformly over an adjustably definable irregular area. In response to this desire various complex rotary sprinklers have heretofore become known to accomplish this purpose. The instant invention is an improvement over such known devices.

The periphery of an irregular area to be watered by a rotary sprinkler is most simply defined by some type of an adjustable cam. Such cams commonly regulate the amount of water flow through rotating nozzle, the angle of the nozzle output relative the earth, or the direction of flow of water from the nozzle ori' fice. The instant invention is of the first type and by reason of mechanical function obviously distinguishable from the latter two classes.

The cam of the instant invention is distinguishable from other known members of its class in that it provides a circularly arrayed spring band that may be readily positioned in varying vertical attitudes to cause a cam, through appropriate mechanical linkage with a valve, to regulate volume of water flow through the sprinkler nozzle. The cam flower may be manually moved by an operator during operation of thesprinkler to, allow the operator to visually determine the area wetted to thusly determine desired cam position. The manualvisual setting of the sprinkler may be accomplished during sprinkler operation without wetting the operator. The rotation of the sprinkler head is powered by direct mechanical communication with a water motor in the input circuitry.

My sprinkler is further distinguished from members of its class in that it provides a second positively driven, disk cam with its periphery interposed in the nozzle output to distribute its output uniformly over the area to be watered but yet not determine the area to be watered. The cam allows a substantially uniform distribution of water over the entire area serviced, whereas other prior art devices having an aerial distributor of one sort or another have provided a haphazard distribution of water or else have used the cam to define the periphery of the watered area. This distribution cam may be removed to allow simple accurate definition of the periphery of the serviced area.

SUMMARY OFINVENTION The instant invention was conceived to provide a positively mechanically driven rotatable sprinkler having a first adjustable, manually settable cam to define the periphery of a sprinkled area and a second positively driven disk cam associated with the nozzle output to uniformly distribute water within the area sprinkled.

To accomplish this I provide a cylindrical body, having a lower input chamber and an upper dispersal chamber, rotatably mounting a sprinkler head for radial distribution of water. The lower input chamber communicates from a pressurized water source through a water motor which mechanically communicates through appropriate reduction gearing to the sprinkler head to cause its rotation upon flow of water through the sprinkler. The water motor in turn provides its output to the dispersal chamber.

An adjustable'sprinkler nozzle hydraulically communicates, through an adjustable valve, with the dispersal chamber. Flow through the valve is regulated by appropriate mechanical linkage with a cam follower that describes a vertically variable circular path about the sprinkler head. A circularly disposed cam V 2 spring, supported on land adjustably vertically positionable relative to the sprinkler body, communicates with the cam follower to determine its vertical position and this position in turn is mechanically communicated to the sprinkler nozzle valving means to associate the vertical position of the cam follower at any particular radial position to the dispersement of water at that position, thusly determining the periphery of the watered area. The cam spring is manually movable to a particular vertical position and maintained in this position by appropriate mechanical bias.

A disklike distribution cam is associated with the sprinkler nozzle in such fashion that its periphery rotatably interposes within the output of the nozzle to cyclically determine output deposition within the periphery of the sprinkled area previously defined. The distribution cam is rotatably carried by the rotating sprinkler nou le and positively driven by mechanical linkage with the stationary sprinkler body.

In providing such a mechanism it is:

A principal object of my invention to provide a positively driven rotary sprinkler having an adjustable cam controlled valving system of particular structure to determine the flow of water through thesprinkler and thusly the periphery of the area watered. g

A further object of my invention to provide such a sprinkler with a valving cam that is readily manually movable during operation to allow visual definition of the area sprinkled.

A still further object of my invention to provide such a sprinkler that allows manual setting during operation without wetting the operator.

A further object of my invention to provide such a sprinkler that has an aerial distributing cam associated with the nozzle output such that theperiphery of the distributing cam moves within the nozzle output to cyclically distribute the output within the periphery of the sprinkled area to cause substantially uniform water distribution.

A still further object of my invention to provide such a device that is of new and novel design, of sturdy and durable nature, of simple and economic manufacture, and one otherwise well adapted to the uses and purposes for which it is intended. A

Other and further objects of my invention will appear from the following specification and accompanying drawings which form a part hereof. In carrying out the objects of my invention, however, it is to be understood that its essential features are susceptible of change: in design and structural arrangement with only one preferred and practical embodiment being illustrated in the accompanying drawings, as required.

BRIEF DESCRIPTION OF DRAWINGS In the accompanying drawings, wherein like numbers of reference refer to similar parts throughout:

FIG. 1 is a vertical'orthographic plan view of the sprinkler of my invention, with some parts hidden by the cam disk shown in dotted outline to illustrate the various parts, their configuration and relationship from this aspect.

FIG. 2 is a vertical cross-sectional view of sprinkler of FIG. 1 taken on the plane 2-2 of FIG. 1 in the direction indicated by the arrows thereon.

FIG. 3 is a horizontal cross-sectional view of the sprinkler of FIG. 1 taken on the line 33 of FIG. 2 in the direction indicated by the arrows thereon, to show particularly the water motor and its associated structures.

FIG. 4 is an isometric view of the cam follower of my device, more particularly showing its nature and detail.

FIG. 5 is a plan view of the aerial distribution cam showing particularly its peripheral configuration.

FIG. 6 is an isometric view of the water motor impeller and associated gearing structure.

FIG. 7 is a partially cut away isometric view of a spring cam holder, more particularly showing its nature and operation.

Hun-v1 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in more detail and particularly to that of FIG. 2, it will there be seen that my invention generally comprises body defining input chamber 11 and dispersal chamber 12 and rotatably supporting sprinkler head 13 with associated internal driving mechanism 14, external peripheral pattern defining mechanism 15, and serial patterning mechanism 16.

Body 10 is a shell-like rigid element, in this instance of cylindrical shape, defining the input and dispersal chambers 11 and 12 and providing support for the entire sprinkler device. The body is formed with bottom element 17 structurally communicating with cylindrical side element 18 having in its upper portion lid groove 19 to receive lid 20, releasably maintained in position by plural studs 21 threadly communicating therebetween, all to define the input and dispersal chambers.

A thin medial septum 22 is supported in the middle portion of the input chamber to aid in providing support for various operative elements. This septum is releasably fastened on the upper surface of septum dogs 23 by threaded studs 24 extending therebetween. Both top and septum 22 are provided with appropriate circular orifices 25, 26 to rotatably journal the vertical shaft of the sprinkling head. The septum is provided with additional holes 27 to receive various shafts of the sprinkler driving mechanism.

Input chamber 11 is defined in the lower interior portion of body 10 between bottom 17 and chamber divider 28. An external fixture 29, structurally carried by body 10 and adapted to releasably fasten to a pressurized water source (not shown) communicates through input channel 30 to water motor chamber 31.

Preferably a spring biased diverting vane is interposed in the mouth of the orifice to divert water flow directly upon the water motor vanes and thusly assure positive operation of the sprinkler at low flow rates.

Water motor rotor 32 is irrotatably carried on water motor shaft 33 journaled in bottom 17 and septum 22 so as to allow the rotor to rotate in the motor chamber. A portion of chamber divider 28 over the water motor is provided with orifice 34 to allow water to flow freely from the water motor chamber into the dispersal chamber.

Dispersal chamber 12 defines an enclosed volume for storage of water before dispersement and provides an operative area for the various mechanical devices of the sprinkler. The dispersal chamber is divided into upper portion 36 carrying the sprinkler head driving mechanism and lower portion 37 carrying the valved input mechanism of the sprinkler head.

Sprinkler head 13 is the complexly shaped structure illustrated in FIG. 2, somewhat of the shape of a Y, having depending body portion 38 communicating with angularly disposed sprinkler arm 39, to define water channel 40 communicating to adjustable dispersal head 41, and control arm 42 extending angularly to both. Depending body portion 38 extends through holes 25, 26 in the top and septum 22 and is maintained in appropriate vertical alignment therein by external retaining ring 43 releasably carried on the outside of the top in angular groove 44 and the clutching structure therebelow, all rotatably supporting the sprinkler head in the body structure in proper vertical position.

The valving structure associated with the sprinkler head comprises conical valve 45 adapted to fit in seat 46 in the lowermost portion of depending body 38. Elongate valve stem 48 is slidably supported in valve stem bearing 49 in the uppermost portion of body 38 between sprinkler arm and control arm to serve as a part of the peripheral patterning mechanism. Preferably sprinkler arm 39 has enlarged internal chamber 50 to provide for more even water flow and continuous operation of the sprinkler.

Driving mechanism 14 includes spaced parallel jack shafts 51 journaled between septum 22 and bottom 17 and jack shaft 52 rotatably journaled in the medial portion of water motor power shaft 33. Upper portion 53 of power shaft 33 is geared to mesh with gear 54 rotatably carried on shaft 51. Gear 54 irrotatably communicates with smaller gear 55 on the same shaft and this in turn intermeshes with gear 56 irrotatably communicating with gear 57 both rotatably carried on shaft 52. Gear 56 irrotatably communicates with gear 57 on shaft 52 and gear 57 intermeshes with gear 58 on shaft 51. This gear 58 irrotatably communicates with gear 59 which intenneshes with gear 60 carried on shaft 52 to irrotatably communicate with gear 61 on that shaft. Gear 61 intermeshes with driving gear 62 rotatably carried by body 38 of sprinkler head structure 13. Clutch 63 provides element 63a irrotatably communicating with the upper surface of driving gear 62 and element 63b irrotatably communicates with depending body 38 of the sprinkler head. Water pressure present in the sprinkler the valving mechanism, or some mechanical biasing device such as a spring (not shown), will cause an upward force upon the large gear 62 to bring the clutch elements into frictional engagement. With this mechanism then as the water motor operates upon the input of water through the sprinkler, the motion is transmitted through the reduction gearing train to gear 62 and thence through clutch 63 to cause the head to rotate.

The structure heretofore described has, at least in its essence, been known in sprinkling devices of the prior art. The improvements of my invention comprises the improved peripheral patterning mechanism and the addition of the aerial patterning mechanism to sprinklers of the type specified.

Peripheral patterning mechanism 15 includes cylindrical, stationery cam support 64 structurally maintained on the upper surface of top 20 in a position concentric about the axis of rotation of sprinkler head structure 13. The outer surface of the cam support is provided with plural, spaced, alternating grooves 65 and ridges 66, each describing one of a series of parallel spaced, vertical circles. The spacing between ridges and grooves defines the fineness of positioning of the circular cam, and therefore, should be relatively small, say in the neighborhood of less than a quarter of an inch. Plural, cylindrical segment cam holders 67, having grooves 68 and ridges 69 of a nature to mate with those of the cam support, are positioned about the periphery of the cam support. Each cam holder 67 has an interior void 70 with relatively thin outer shell 71 defining slot 72 vertically oriented and of a size appropriate to allow slight vertical sliding motion of spring holding dogs 73 therealong to allow for a smoother path of the cam spring than would result were the dogs stationarily positioned in the cam holder 67.

Each holding dog 73 communicates with continuous band tension spring cam 74 of length such that when all cam holder elements are positioned as illustrated in FIG. 1, the spring is under some tension. This tension should be a few pounds, to allow the cam holders to be moved vertically relative the cam support 64 by manual manipulation, but yet sufficient to bias the cam holders so that they will not be accidentally moved by normal operation of the device.

Cam follower 75 comprises L-shaped bell crank 76 having its innermost end pivotably supported by pin 77 on support arm 78 and being of the configuration illustrated in FIG. 2 to extend to a position outwardly adjacent spring cam 74. intermediate pivot arm 77 and depending arm 79, the bell crank pivotably communicates with the uppermost portion of valve stem 78 by pin 80 extending therebetween. The uppermost extension of control arm 42 of the sprinkler head provides yoke 81 having pin 82 in its uppermost portion to limit the upward extension of the cam follower. Handle 83 extends upwardly from the outermost extension of the bell crank to aid in manual manipulation during the setting operation. The lower portion of depending arm 79 journals paired, opposed grooved wheels 84 upon axles 85 in such position as to rollably support the wheels about cam spring 74 to provide the actual cam follower. With this arrangement of parts then, the vertical position of spring cam 74 will be transmitted through the cam follower bell crank to vertically move the sprinkler valve to regulate water flow through the sprinkler head.

Aerial patterning mechanism 16 is associated with the sprinkling arm of sprinkler head 13 to provide substantially uniform distribution of water within the periphery of the sprinkled area. The system provides flat peripheral cam 86 having outer periphery 87 and medial hole 88 to allow releasable, irrotatable mounting upon cam shaft 89, which is journaled through the medial portion of sprinkler arm 39 by positioning the cam between nuts 90 and 91 threadedly engaged upon the end part of shaft 89. The lowermost portion of shaft 89 irrotatably mounts cog gear 92 to intermesh with interior conical gear 93 extending about the inner surface of cylindrical cam support 64. With arrangement of elements then, as the sprinkler head rotates, conical gear 93 will remain stationary and cog gear 92 will then of necessity rotate shaft 89 and thusly cam 86. The cam positioning is such that the plane of the cam meets the axis of a stream of dispersed water at an acute angle, with the cam periphery in the dispersed water stream.

Periphery 87 of cam 86 is shaped in the nature of a spiral, as illustrated in the plan diagram of the device of FIG. 5. The cam is so positioned and its surface so configured that when the innermost portion of the spiral intersects the water stream substantially all of the water dispersed from sprinkler head 41 will be dispersed at the periphery of the pattern watered, while substantially all of the water from the dispersal head, when the outermost portion of the cam be in the stream, will be dispersed immediately adjacent the sprinkler. The portion of the cam between these two extremes is a continuous curve such as a spiral to provide a substantially uniform distribution of water over the watered area. Obviously other types of cams might serve a similar function, depending upon the configuration, relationship and variation between the different elements. My cam rotates at a speed different from the speed of rotation of the sprinkler head so that the sprinkled pattern will not be identical in succeeding cycles.

Having thusly described the structure of my device, its operation may be understood:

A device configured as specified is attached to a source of pressurized water (not shown) by fixture 29 and the water allowed to flow into the sprinkler mechanism. An operator may then stand at the side opposite sprinkler arm 39 to adjust the sprinkler.

To do this preferably, but not necessarily, distribution cam 86 is removed so that water dispersed through dispersal head 41 will extend to its fullest extent. The operator then may manually manipulate handle 83 of cam follower 75 to vertically move the cam and simultaneously manually move sprinkler head 13 or allow it to move in a rotatable fashion. As the cam follower engages a particular section of cam spring 74 adjacent a particular cam holder segment 67, the handle is moved vertically until the water dispersed from head 41 waters the desired periphery. This process is repeated with. each cam holder segment so that the cam spring 74 will define a cylindrical vertically varying path in space that may be related by the cam follower through its mechanical linkage to the valving mechanism to define a particular area to be sprinkled.

After the setting operation is accomplished, the aerial dispersal cam 86 is repositioned as shown in FIG. 2. This cam will then rotate with its periphery in the stream flowing from dispersal head 41 to cause the stream periodically to be diverted inwardly from its outermost position so that all area within the periphery of the sprinkled area will be substantially uniformly watered.

After setting, water will flow through the sprinkler input channel 30 and thencely water motor chamber 31, to cause the motor to rotate and thusly by the linkage therebetween to cause the rotation of sprinkler head 13. The device then, so long as pressurized water be supplied to it, will continue to operate to uniformly sprinkle the particular area defined as aforesaid.

lt is to be particularly noted from the foregoing that my sprinkler may be readily set by an operator in a short period of time by simple operation without becoming wetted by the sprinkler.

It is further to be noted that the sprinkler stream will be cyclically diverted from the periphery of an area watered to its innermost portions, the cycle varying from that of the sprinkler head, so that all area within the boundaries watered will be substantially uniformly watered.

Although the foregoing specification is necessarily of a detailed nature so that a specific embodiment of my invention might be set forth as required, it is to be remembered that various modifications of detail and changes and multiplication of parts may be resorted to without departing from its spirit, essence, and scope.

Having thusly described my invention, what I desire to protect by Letters Patent, and

What I claim is: i

l. in a sprinkler system of the type having a body defining an input chamber communicating with a dispersal chamber through a water motor to provide rotation for a sprinkler head rotatably journaled in the body for rotation about a vertical axis in response to motion of the water motor, with adjustable valving means regulating the flow of water through the sprinkler head, the improvement including a peripheral patterning mechanism comprising:

a cylindrical cam support, concentric about the axis of rotation of the sprinkler head, having alternating, spaced parallel grooves and ridges in the outer surface thereof; plural segmented cam holders, having spaced parallel grooves and ridges about their inner surface adapted to mate with the grooves and ridges of the cam support, extending in adjacent relationship about the outer surface of the cam positioner, each cam holder communicating for vertical positioning with an outwardly adjacent, continuous band, tension spring cam of length such as to maintain in the cam holders under some tension immediately outwardly adjacent the cam positioner but yet allow their manual motion relative thereto; and

a cam follower irrotatably carried by the sprinkler head to cyclically relate the vertical positioning of the tension spring cam to the valving means to determine flow through the sprinkler head.

2. The invention of claim 1 wherein the communication between cam holders and cam comprises:

dogs associated with each cam holder, structurally communicating with the tension spring and extending radially inwardly therefrom to communicate with a vertical slot in the cam holder to'allow limited vertical sliding motion between cam dog and cam holder.

3. The invention of claim 1 having an aerial patterning mechanism comprising:

a fiat disklike rotatable cam having its periphery interposed in the sprinkler flow to divert such flow from maximum outward dispersion in one extreme cam position to maximum inward dispersion at the other extreme cam position with continuous variation therebetween; and

means of rotating the cam.

4. The invention of claim 3.wherein the rotatable cam is releasable and irrotatably carried by a shaft, journaled for rotation in the sprinkler head, irrotatably carrying an external gear meshing with an internal gear structurally curved by the sprinkler body to curve rotation of the cam in response to rotation of the sprinkler head.

5. The invention of claim 4 wherein the cam has a spiral periphery and revolves-at a rotary speed different from the rotary speed of the sprinkler head.

6. A rotatable sprinkler to uniformly distribute water within an irregularly shaped area, comprising, in combination:

a rigid cylindrical body defining an input chamber in the lower portion communicating through a water motor to a dispersal chamber in the upper portion;

a sprinkler head rotatably mounted in the body with its lower portion communicating through a valving mechanism to the dispersement chamber;

driving mechanism linking the water motor to the sprinkler head to cause rotation of the sprinkler head upon the flow of water through the sprinkler;

peripheral patterning mechanism associated with the sprinkler head including: a cylindrical cam support carried on the upper surface of a cam follower mechanically communicating between the cam and the sprinkler valving mechanism to regulate flow therethrough to determine the area watered by the sprinkler head in response to vertical positioning of the spring cam, and

an aerial patterning mechanism comprising a spirally shaped cam rotatably mounted on he sprinkler head to interpose the cam periphery in the stream of flow from the sprinkler head to cyclically divert the flow continuously from an outermost position to an innermost position, the cam having associated mechanical linkage communicating with the sprinkler body to cause cam rotation in response to the rotation of the sprinkler head, but at a different rotary speed.

Hun-n 

1. In a sprinkler system of the type having a body defining an input chamber communicating with a dispersal chamber through a water motor to provide rotation for a sprinkler head rotatably journaled in the body for rotation about a vertical axis in response to motion of the water motor, with adjustable valving means regulating the flow of water through the sprinkler head, the improvement including a peripheral patterning mechanism comprising: a cylindrical cam support, concentric about the axis of rotation of the sprinkler head, having alternating, spaced parallel grooves and ridges in the outer surface thereof; plural segmented cam holders, having spaced parallel grooves and ridges about their inner surface adapted to mate with the grooves and ridges of the cam support, extending in adjacent relationship about the outer surface of the cam positioner, each cam holder communicating for vertical positioning with an outwardly adjacent, continuous band, tension spring cam of length such as to maintain the cam holders under some tension immediately outwardly adjacent the cam positioner but yet allow their manual motion relative thereto; and a cam follower irrotatably carried by the sprinkler head to cyclically relate the vertical positioning of the tension spring cam to the valving means to determine flow through the sprinkler head.
 2. The invention of claim 1 wherein the communication between cam holders and cam comprises: dogs associated with each cam holder, structurally communicating with the tension spring and extending radially inwardly therefrom to communicate with a vertical slot in the cam holder to allow limited vertical sliding motion between cam dog and cam holder.
 3. The invention of claim 1 having an aerial patterning mechanism comprising: a flat disk-like rotatable cam having its periphery interposed in the sprinkler flow to divert such flow from maximum outward dispersion in one extreme cam positioN to maximum inward dispersion at the other extreme cam position with continuous variation therebetween; and means of rotating the cam.
 4. The invention of claim 3 wherein the rotatable cam is releasable and irrotatably carried by a shaft, journaled for rotation in the sprinkler head, irrotatably carrying an external gear meshing with an internal gear structurally curved by the sprinkler body to curve rotation of the cam in response to rotation of the sprinkler head.
 5. The invention of claim 4 wherein the cam has a spiral periphery and revolves at a rotary speed different from the rotary speed of the sprinkler head.
 6. A rotatable sprinkler to uniformly distribute water within an irregularly shaped area, comprising, in combination: a rigid cylindrical body defining an input chamber in the lower portion communicating through a water motor to a dispersal chamber in the upper portion; a sprinkler head rotatably mounted in the body with its lower portion communicating through a valving mechanism to the dispersement chamber; driving mechanism linking the water motor to the sprinkler head to cause rotation of the sprinkler head upon the flow of water through the sprinkler; peripheral patterning mechanism associated with the sprinkler head including: a cylindrical cam support carried on the upper surface of the body and having plural spaced ridges and grooves about its outer surface communicating with plural cam holders having similar mating spaced ridges and grooves about their inner surfaces, the cam holders being positioned radially, adjacently, outward from the cam support, each cam holder communicating with a continuous band spring cam of such length as to bias the cam holders in adjacency about the cam support but allow vertical motion thereof in response to manual manipulation; a cam follower mechanically communicating between the cam and the sprinkler valving mechanism to regulate flow therethrough to determine the area watered by the sprinkler head in response to vertical positioning of the spring cam, and an aerial patterning mechanism comprising a spirally shaped cam rotatably mounted on the sprinkler head to interpose the cam periphery in the stream of flow from the sprinkler head to cyclically divert the flow continuously from an outermost position to an innermost position, the cam having associated mechanical linkage communicating with the sprinkler body to cause cam rotation in response to the rotation of the sprinkler head, but at a different rotary speed. 